Abstract: A multistage pump according to the present invention has a plurality of intermediate casings (2) formed by press-forming a steel plate. The intermediate casing has a cylindrical side portion (21), a stage flat portion (23) with which an axial end face of an adjacent intermediate casing is held in contact, a stage side portion (24) extending axially from the stage flat portion, and a bottom portion (25) extending radially inward from the stage side portion. A relief plate (30) having an outer circumferential end face which is held in contact with an inner surface of a cylindrical side portion of the adjacent intermediate casing is attached to the bottom portion of the intermediate casing. The relief plate, the stage side portion, the stage flat portion, and the inner surface of the cylindrical side portion of the adjacent intermediate casing form a space in which an O-ring (40) is fitted.

Abstract: A centrifugal pump includes a diffuser section for decreasing a velocity of the fluid discharged from an impeller, a return vane for leading the fluid which has passed through the diffuser section to a discharge side, and a main plate to which the diffuser section and the return vane are fixed.

Abstract: The present invention relates to a centrifugal pump whose components such as an impeller and a casing are manufactured from a sheet metal and a method of manufacturing such a centrifugal pump. The centrifugal pump according to the present invention comprises a diffuser section (11) for decreasing a velocity of the fluid discharged from an impeller, a return vane (14) for leading the fluid which has passed through the diffuser section (11) to a discharge side, a main plate (12) to which the diffuser section (11) and the return vane (14) are fixed, and a structural member (13) for smoothening a step (17) formed in a passage extending from the diffuser section (11) to the return vane (14).

Abstract: An impeller (1) according to the present invention has a disk-like main plate (10), a blade (20) joined to the main plate, and a side plate (30) having a suction port. A boss hole (12) is formed in a central portion of the main plate for attaching a boss which engages with a pump shaft to the boss hole. A step portion (14) is formed around the boss hole, which is formed in the main plate, by drawing.

Abstract: A multistage pump according to the present invention has a plurality of intermediate casings (2) formed by press-forming a steel plate. The intermediate casing has a cylindrical side portion (21), a stage flat portion (23) with which an axial end face of an adjacent intermediate casing is held in contact, a stage side portion (24) extending axially from the stage flat portion, and a bottom portion (25) extending radially inward from the stage side portion. A relief plate (30) having an outer circumferential end face which is held in contact with an inner surface of a cylindrical side portion of the adjacent intermediate casing is attached to the bottom portion of the intermediate casing. The relief plate, the stage side portion, the stage flat portion, and the inner surface of the cylindrical side portion of the adjacent intermediate casing form a space in which an O-ring (40) is fitted.

Abstract: The present invention relates to a fastener and a fastening method for joining together two or more members including at least one complicate-shaped plate. A fastener comprises a cap nut (20) having a main body and a thin-walled portion (24) projecting from the main body, and a bolt (30) screwed into the cap nut (20). The cap nut (20) is fixed to a plate-like member (12) by inserting the thin-walled portion (24) into a through-hole (12a) of the plate-like member (12) and caulking the thin-walled portion (24).

Abstract: An impeller (1) according to the present invention has a disk-like main plate (10), a blade (20) joined to the main plate, and a side plate (30) having a suction port. A boss hole (12) is formed in a central portion of the main plate for attaching a boss which engages with a pump shaft to the boss hole. A step portion (14) is formed around the boss hole, which is formed in the main plate, by drawing.

Abstract: The present invention relates to a fastener and a fastening method for joining together two or more members including at least one complicate-shaped plate. A fastener comprises a cap nut (20) having a main body and a thin-walled portion (24) projecting from the main body, and a bolt (30) screwed into the cap nut (20). The cap nut (20) is fixed to a plate-like member (12) by inserting the thin-walled portion (24) into a through-hole (12a) of the plate-like member (12) and caulking the thin-walled portion (24).

Abstract: A plate heat exchanger for use as an evaporator in a refrigerator including a compressor, a condenser, an expansion valve and the evaporator which cooperate to perform a refrigeration cycle. The plate heat exchanger comprises a plurality of plates stacked on each other to define chambers of a refrigerant and chambers of a medium to be cooled, a refrigerant introduction passage means extending through the plates and provided with orifices for delivering the refrigerant from the refrigerant introduction passage means to the refrigerant chambers, and a refrigerant stirring member for stirring the refrigerant supplied into the refrigerant introduction passage means in the form of a wet steam to make the refrigerant uniform.

Abstract: A pump casing made of sheet metal has an outer casing having a suction nozzle, and an inner casing housed in said outer casing and spaced therefrom. A resilient seal is disposed in a gap defined between the outer casing and an inner casing. An impeller is rotatably disposed in the inner casing with a clearance defined between a liner portion of the inner casing and the impeller. The resilient seal is effective to absorb deformations of the outer casing, such deformations of the outer casing are not transmitted to the inner casing.

Abstract: A pump casing made of sheet metal has an outer casing having a suction nozzle, and an inner casing housed in said outer casing and spaced therefrom. A resilient seal is disposed in a gap defined between the outer casing and an inner casing. An impeller is rotatably disposed in the inner casing with a clearance defined between a liner portion of the inner casing and the impeller. The resilient seal is effective to absorb deformations of the outer casing, such deformations of the outer casing are not transmitted to the inner casing.

Abstract: An interstage casing made of sheet metal includes a cylindrical receptacle-like body having a casing end wall on an end thereof and an open end opposite to The end. The omen end has an axial end surface and a radially inner surface which serve as a member of a spigot joint to be joined to the next interstage casing. The cylindrical receptacle-like body also includes a cylindrical side wall, a cylindrical portion joined between the casing end wall and the cylindrical side wall and having an outside diameter slightly smaller than an inside diameter of the open end, and a flat portion joined to the recessed portion and serving as an end surface of the casing end wall. The flat portion is adapted to be engageable with the end surface of the open end of an adjacent interstage casing. The flat portion has an outside diameter slightly larger than an outside diameter of the open end.

Abstract: A shaft sleeve is made of ceramics and provided in confrontation with a stationary sliding member in a sliding bearing or plain bearing. The shaft sleeve made of ceramics comprises a cylindrical body made of ceramics and having a circular outer surface and a circular inner surface, and an elastic member molded on the inner surface of the cylindrical body and being formed with an inner opening having a shape corresponding to the cross section of a shaft. The shaft sleeve is usable under high temperature conditions and with liquids containing much slurry such as, for example, as a shaft sleeve of a pump.

Abstract: An interstage casing made of sheet metal includes a cylindrical receptacle-like body having a casing end wall on an end thereof and an open end opposite to the end. The open end has an axial end surface and a radially inner surface which serve as a member of a spigot joint to be joined to the next interstage casing. The cylindrical receptacle-like body also includes a cylindrical side wall, a cylindrical portion joined between the casing end wall and the cylindrical side wall and having an outside diameter slightly smaller than an inside diameter of the open end, and a flat portion joined to the recessed portion and serving as an end surface of the casing end wall. The flat portion is adapted to be engageable with the end surface of the open end of an adjacent interstage casing. The flat portion has an outside diameter slightly larger than an outside diameter of the open end.

Abstract: A multistage centrifugal pump has a plurality of series-connected interstage casings of pressed sheet steel housing respective impellers. Each of the interstage casings includes a central cylindrical side wall, a casing end wall, a first cylindrical wall integrally extending from an end of the central cylindrical side wall and joined to the casing end wall, the first cylindrical wall serving as a male member of a spigot joint, and a second cylindrical wall integrally extending from an opposite end of the central cylindrical side wall and having a flange defining an end opening therein, the second cylindrical wall serving as a female member of a spigot joint. The central cylindrical side wall has an outside diameter larger than outside diameters of the first cylindrical wall and the flange. The interstage casing is formed by drawing and bulging, and is not machined to achieve the desired dimensional accuracy.

Abstract: A sheet-metal centrifugal pump casing comprising a casing shell having a suction port and being formed of a steel plate by means of deep drawing using a press, and having a suction flange firmly attached to the suction port of the casing shell is disclosed. The centrifugal pump casing further comprises a partition body firmly attached to the inner surface of the casing shell for partitioning a space within the casing shell into a suction chamber and a pressure chamber, and a diffuser which is integrally extended from the suction side end portion of the partition body and which tapers off toward peripheral edge of said suction port so that an axial gap is formed between the end edge of the diffuser and the peripheral edge of said suction port.

Abstract: A pump casing manufactured by press forming of steel plate and including a volute casing encircling a pump impeller so as to form a fluid path around the pump impeller is disclosed. The cross-sectional area of the fluid path is gradually increased towards a discharge port of the pump casing. The pump casing includes a casing body which is formed at first by press forming a metal plate into a cylindrical cup shape having an opening portion at one side thereof and a closed bottom portion at the other side of the same, and then by press forming the cylindrical cup shaped casing body so as to have a volute portion radially outwardly expanded from a cylindrical surface of the casing body at an axially intermediate portion thereof which radially opposite to the pump impeller, a casing flange outwardly extending from the opening portion and an aperture serving as a suction port at the bottom portion.

Abstract: A pump impeller manufactured by press forming of steel plate and comprising a boss formed with a central bore for connecting the boss to a main shaft of the pump through key and key way engagement, and a main shroud fixed to the boss is disclosed. The impeller is characterized in that the boss is formed with a polygonal portion on the periphery of the boss and the main shroud is formed at central portion thereof with a polygonal recess fitting to the polygonal portion of the boss. A retainer plate is mounted on the boss at an end portion thereof opposite to an end portion from which the main shroud is fitted to the boss and is connected by welding to the main shroud. Thereby, since the power is transmitted from the boss to the main shroud through polygonal surfaces, no substantial stress concentration occurs at the power transmitting area.